3.3 nissan frontier 80k miles
C1=165
C2=150
C3=175
C4=150
C5=165
C6=150
Compression held on all cylinders
Had a "Pop" sound on 3 and 6 (While Comp Testing)
Initial reason for the test is CEL and a "Random Misfire" code
Does seem heavy on fuel consumption
Any thoughts on what might be the cause of the code?
Are the readings satisfactory?
Seems to run fine (maybe a little rich) but cant get it plated with the trouble codes
TIA
The difference between 150 and 175 is actually borderline bad. But they can misfire for various reasons on those off in the ignition coils can go bad have those check first also check for any vacuum leaks and do a head gasket leak test doesn't my video how to tell if your headgasket is blown
That’s 15% compression loss - at 16% in many places that’s already considered “no compression”.
Is that the supercharged version?
A clogged or malfunctioning PCV valve can cause lots of weird problems. It is just a possibility suggestion. It is often overlooked for such a small, inexpensive item. Which is why I use a new one with each oil/filter change.
Closing this post
Turns out the new FI's I installed were the problem all along
They came in Nissan packaging and tested good (electrically)
Apparently, they were for a different vehicle or I was ripped off by the seller
Trucks running better than ever now
Thanks for all the help
T
Hey Scotty,
Wanted to circle back with this problem
Ive checked all the vacuum, with a home made smoke machine (there were a few loose)
Still getting misfire code
I did a leak down test on the offending cylinder (3)
While removing the plugs Cylinder 5 was pretty fouled
The leak down test was performed on 3 (the one the obdii reader identified) and cylinder 5 (fouled plug)
The results were less than 20% loss on both
While searching the web I came upon the oil recommendation of 5w-30, 10w-30,10w-40
as well as a synthetic 5w-30
The truck spent its life in the SE (Alabama, Mississippi)
Do you think going with 10w-40 would help with curing the misfire code?
T
eww. Did you just say "Circle Back"
That’s 15% compression loss - at 16% in many places that’s already considered “no compression”.
Is that the supercharged version?
No not the SC version
From what I understand the reading (leak-down) was well within acceptable % loss
To your point, at what % compression difference would a CEL come on?
The LD test seems to indicate a minor leak through the oil dipstick
It was so minor I am not sure it was actual or my imagination
As it may be the dipstick that would indicate worn, stuck or burnt rings?
Would the thicker visc 10w-40 help elevate the misfire issue?
Thnx
Scotty,
As mentioned above
The leakdown test showed no problems (on all 6 cylinders)
The #5 plug was fouled
after cleaning the plugs the CEL cleared
LTFT bnk1 showed it was -10ish (STFTB1 was -15ish), after running awhile and w/CEL on
Where to go from here?
A faulty injector on 5?
Im assuming there was a problem on th bnk2 test results (the plugs are buried deep below the intake manifold)
Ive read somewhere the cheaper code readers can misidentify a cylinder
Im at a loss
compression on bank 1 was passable
Thnx
For reference
Ive changed
injectors (I did have a failure on one of the new ones)
Dist
Plugs and wires
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Have you replaced your PCV valve?
Have you replaced your PCV valve?
Do you think that would effect a single cylinder?
As mentioned above
The leakdown test showed no problems (on all 6 cylinders)
The #5 plug was fouled
after cleaning the plugs the CEL cleared
LTFT bnk1 showed it was -10ish (STFTB1 was -15ish), after running awhile and w/CEL on
Where to go from here?
A faulty injector on 5?
Im assuming there was a problem on th bnk2 test results (the plugs are buried deep below the intake manifold)
Ive read somewhere the cheaper code readers can misidentify a cylinder
Im at a loss
compression on bank 1 was passable
Do you think its the Cat?
Is there a way to check it w/o removing?
Thnx